﻿#region File and License Information
/*
<File>
	<License Type="BSD">
		Copyright © 2009 - 2012, Outcoder. All rights reserved.
	
		This file is part of Calcium (http://calciumsdk.net).

		Redistribution and use in source and binary forms, with or without
		modification, are permitted provided that the following conditions are met:
			* Redistributions of source code must retain the above copyright
			  notice, this list of conditions and the following disclaimer.
			* Redistributions in binary form must reproduce the above copyright
			  notice, this list of conditions and the following disclaimer in the
			  documentation and/or other materials provided with the distribution.
			* Neither the name of the <organization> nor the
			  names of its contributors may be used to endorse or promote products
			  derived from this software without specific prior written permission.

		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
		ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
		WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
		DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
		DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
		(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
		LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
		ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
		(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
		SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	</License>
	<Owner Name="Daniel Vaughan" Email="danielvaughan@outcoder.com" />
	<CreationDate>2012-05-23 10:47:09Z</CreationDate>
</File>
*/
#endregion

using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Interactivity;
using System.Windows.Media;

namespace Outcoder.UI.Xaml
{
	public class TextBoxBehaviors
	{
		#region Watermark Behavior

		public static readonly DependencyProperty WatermarkBehaviorProperty = DependencyProperty.RegisterAttached(
			"WatermarkBehavior",
			typeof(WatermarkBehavior),
			typeof(TextBoxBehaviors),
			null);

		public static readonly DependencyProperty WatermarkTextProperty = DependencyProperty.RegisterAttached(
			"WatermarkText",
			typeof(string),
			typeof(TextBoxBehaviors),
			new PropertyMetadata(HandleWatermarkTextChanged));

		public static string GetWatermarkText(DependencyObject dependencyObject)
		{
			return (string)dependencyObject.GetValue(WatermarkTextProperty);
		}

		public static void SetWatermarkText(DependencyObject dependencyObject, string value)
		{
			dependencyObject.SetValue(WatermarkTextProperty, value);
		}

		static void HandleWatermarkTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			var textBox = d as TextBox;
			WatermarkBehavior behavior = GetOrCreateWatermarkBehavior(textBox);
			behavior.WatermarkText = e.NewValue.ToString();
		}

		static WatermarkBehavior GetOrCreateWatermarkBehavior(TextBox textBox)
		{
			var behavior = textBox.GetValue(WatermarkBehaviorProperty) as WatermarkBehavior;

			if (behavior == null)
			{
				behavior = new WatermarkBehavior();
				behavior.Attach(textBox);
				textBox.SetValue(WatermarkBehaviorProperty, behavior);
			}

			return behavior;
		}

		
		#endregion

		#region TextCleared

		static readonly DependencyProperty TextClearedProperty
			= DependencyProperty.RegisterAttached(
				"TextCleared",
				typeof(bool),
				typeof(TextBoxBehaviors),
				new PropertyMetadata(false));

		public static bool GetTextCleared(Control target)
		{
			return (bool)target.GetValue(TextClearedProperty);
		}

		public static void SetTextCleared(Control target, bool value)
		{
			target.SetValue(TextClearedProperty, value);
		}

		#endregion

		#region EnterKeyCommand

		static readonly DependencyProperty EnterKeyCommandBehaviorProperty
			= DependencyProperty.RegisterAttached(
				"EnterKeyCommandBehavior",
				typeof(EnterKeyCommandBehavior),
				typeof(TextBoxBehaviors),
				new PropertyMetadata(null));

		static readonly DependencyProperty EnterKeyCommandProperty 
			= DependencyProperty.RegisterAttached(
				"EnterKeyCommand",
				typeof(ICommand),
				typeof(TextBoxBehaviors),
				new PropertyMetadata(OnEnterKeyCommandChanged));


		public static ICommand GetEnterKeyCommand(TextBox target)
		{
			return (ICommand)target.GetValue(EnterKeyCommandProperty);
		}

		public static void SetEnterKeyCommand(TextBox target, ICommand value)
		{
			target.SetValue(EnterKeyCommandProperty, value);
		}

		static void OnEnterKeyCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			TextBox textBox = d as TextBox;
			if (textBox == null)
			{
				throw new InvalidOperationException("EnterKeyCommandBehavior can only be used on a TextBox.");
			}

			EnterKeyCommandBehavior behavior = GetOrCreateEnterKeyCommandBehavior(textBox);

			if (e.NewValue != null)
			{
				behavior.Command = (ICommand)e.NewValue;
				textBox.SetValue(EnterKeyCommandBehaviorProperty, behavior);
				behavior.Attach();
			}
			else
			{
				textBox.SetValue(EnterKeyCommandBehaviorProperty, null);
				behavior.Detach();
			}
		}

		/// <summary>
		/// Retrieves the behavior if it has been previously associated, or creates a new behavior instance.
		/// </summary>
		static EnterKeyCommandBehavior GetOrCreateEnterKeyCommandBehavior(TextBox target)
		{
			var behavior = target.GetValue(EnterKeyCommandBehaviorProperty) as EnterKeyCommandBehavior;

			if (behavior == null)
			{
				behavior = new EnterKeyCommandBehavior {Target = target};
			}

			return behavior;
		}

		public class EnterKeyCommandBehavior
		{
			public TextBox Target { get; set; }
			public ICommand Command { get; set; }

			public void Attach()
			{
				Target.KeyDown += OnKeyDown;
			}

			public void Detach()
			{
				Target.KeyDown -= OnKeyDown;
			}

			void OnKeyDown(object sender, KeyEventArgs e)
			{
				if (e.Key == Key.Enter)
				{
					Page parent = Target.GetVisualAncestors<Page>().FirstOrDefault();
					if (parent != null)
					{
						parent.Focus();
					}

					Command.Execute(Target.Text);
					if ((bool)Target.GetValue(TextClearedProperty))
					{
						Target.Text = string.Empty;
					}
				}
			}
		}

		#endregion
	}

	public sealed class WatermarkBehavior : Behavior<TextBox>
	{
		const string nonBreakingSpace = "\x00A0";
		Brush foregroundBrush;

		/// <summary>
		/// Text property - set in XAML
		/// </summary>
		public static readonly DependencyProperty WatermarkTextProperty =
			DependencyProperty.RegisterAttached("WatermarkText", typeof(string), typeof(WatermarkBehavior),
												new PropertyMetadata(null, HandleWatermarkTextChanged));

		public string WatermarkText
		{
			get
			{
				return (string)GetValue(WatermarkTextProperty);
			}
			set
			{
				SetValue(WatermarkTextProperty, value);
			}
		}

		/// <summary>
		/// Backing storage for IsWatermarkVisible property.
		/// </summary>
		public static readonly DependencyProperty WatermarkVisibleProperty =
			DependencyProperty.Register("WatermarkVisible", typeof(bool), typeof(WatermarkBehavior),
										new PropertyMetadata(default(bool), HandleWatermarkVisibilityChanged));

		static void HandleWatermarkVisibilityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			var behavior = (WatermarkBehavior)d;
			if ((bool)e.NewValue)
			{
				if (!behavior.SetWatermarkTextIfTextboxIsEmpty())
				{
					behavior.WatermarkVisible = false;
				}
			}
			else
			{
				behavior.RemoveWatermarkText();
			}
		}

		/// <summary>
		/// Returns whether the watermark is currently visible.  This can be databound to test within a ViewModel.
		/// This should be used to determine if the Text property of the TextBox is valid or not.
		/// </summary>
		public bool WatermarkVisible
		{
			get
			{
				return (bool)GetValue(WatermarkVisibleProperty);
			}
			set
			{
				SetValue(WatermarkVisibleProperty, value);
			}
		}

		public static bool IsWatermarkVisible(TextBox textBox)
		{
			var behaviors = Interaction.GetBehaviors(textBox);
			var behavior = (WatermarkBehavior)behaviors.FirstOrDefault(b => b is WatermarkBehavior);

			if (behavior == null)
			{
				behavior = (WatermarkBehavior)textBox.GetValue(TextBoxBehaviors.WatermarkBehaviorProperty);
			}

			if (behavior != null && behavior.AssociatedObject == textBox)
			{
				return behavior.WatermarkVisible;
			}
			
			return false;
		}

		public static string GetText(TextBox textBox)
		{
			return (string)textBox.GetValue(WatermarkTextProperty);
		}

		public static void SetText(TextBox textBox, string text)
		{
			textBox.SetValue(WatermarkTextProperty, text);
		}

		/// <summary>
		/// The color of the watermark text. Default is gray.
		/// </summary>
		public static readonly DependencyProperty WatermarkColorProperty =
			DependencyProperty.Register("WatermarkColor", typeof(Brush), typeof(WatermarkBehavior),
							new PropertyMetadata(new SolidColorBrush(Colors.Gray), HandleWaterMarkColorChanged));

		static void HandleWaterMarkColorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			var behavior = (WatermarkBehavior)d;
			if (behavior.AssociatedObject != null)
			{
				behavior.SetTextBoxForgroundIfWatermarkVisible();
			}
		}

		public Brush WatermarkColor
		{
			get
			{
				return (Brush)GetValue(WatermarkColorProperty);
			}
			set
			{
				SetValue(WatermarkColorProperty, value);
			}
		}

		/// <summary>
		/// This is called when the watermark text is changed on either a WatermarkBehavior
		/// or on a TextBox directly to attach/detach the behavior.
		/// </summary>
		/// <param name="d"></param>
		/// <param name="e"></param>
		static void HandleWatermarkTextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
		{
			var behavior = d as WatermarkBehavior;
			if (behavior != null)
			{
				if (behavior.AssociatedObject != null)
				{
					behavior.WatermarkVisible = true;
				}
			}
			// Attach/Detach request
			else
			{
				TextBox textBox = d as TextBox;
				if (textBox != null)
				{
					string text = (e.NewValue ?? string.Empty).ToString();
					BehaviorCollection behaviors = Interaction.GetBehaviors(textBox);
					var watermarkBehavior = (WatermarkBehavior)behaviors.FirstOrDefault(b => b is WatermarkBehavior);

					if (string.IsNullOrWhiteSpace(text))
					{
						if (watermarkBehavior != null)
						{
							behaviors.Remove(watermarkBehavior);
						}
					}
					else
					{
						if (watermarkBehavior == null)
						{
							watermarkBehavior = new WatermarkBehavior { WatermarkText = text };
							behaviors.Add(watermarkBehavior);
						}
						else
						{
							watermarkBehavior.WatermarkText = text;
						}
					}

				}
			}
		}

		protected override void OnAttached()
		{
			AssociatedObject.GotFocus -= HandleTextBoxGotFocus;
			AssociatedObject.GotFocus += HandleTextBoxGotFocus;
			AssociatedObject.LostFocus -= HandleTextBoxLostFocus;
			AssociatedObject.LostFocus += HandleTextBoxLostFocus;
			AssociatedObject.TextChanged -= HandleTextBoxTextChanged;
			AssociatedObject.TextChanged += HandleTextBoxTextChanged;
			AssociatedObject.Loaded -= HandleTextBoxLoaded;
			AssociatedObject.Loaded += HandleTextBoxLoaded;

			if (AssociatedObject.Parent != null)
			{
				WatermarkVisible = true;
			}
		}

		/// <summary>
		/// Called when the TextBox is loaded - we associate the watermark
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="routedEventArgs"></param>
		void HandleTextBoxLoaded(object sender, RoutedEventArgs routedEventArgs)
		{
			WatermarkVisible = true;
		}

		/// <summary>
		/// Override called when behavior is detached
		/// </summary>
		protected override void OnDetaching()
		{
			AssociatedObject.GotFocus -= HandleTextBoxGotFocus;
			AssociatedObject.LostFocus -= HandleTextBoxLostFocus;
			AssociatedObject.TextChanged -= HandleTextBoxTextChanged;

			WatermarkVisible = false;
		}

		bool SetWatermarkTextIfTextboxIsEmpty()
		{
			if (string.IsNullOrEmpty(AssociatedObject.Text))
			{
				Brush textBoxForeground = AssociatedObject.Foreground;
				foregroundBrush = textBoxForeground != Control.ForegroundProperty.GetMetadata(typeof(TextBox)).DefaultValue
									? textBoxForeground : null;
				AssociatedObject.Foreground = this.WatermarkColor;
				AssociatedObject.Text = this.WatermarkText + nonBreakingSpace;
				return true;
			}

			return false;
		}

		void SetTextBoxForgroundIfWatermarkVisible()
		{
			if (!string.IsNullOrEmpty(AssociatedObject.Text))
			{
				if (WatermarkVisible)
				{
					AssociatedObject.Foreground = this.WatermarkColor;
				}
			}
		}

		bool RemoveWatermarkText()
		{
			if (!string.IsNullOrEmpty(AssociatedObject.Text))
			{
				if (AssociatedObject.Text == WatermarkText + nonBreakingSpace)
				{
					if (foregroundBrush != null)
					{
						AssociatedObject.Foreground = foregroundBrush;
					}
					else
					{
						AssociatedObject.ClearValue(Control.ForegroundProperty);
					}
					AssociatedObject.Text = string.Empty;
					return true;
				}
			}

			return false;
		}

		void HandleTextBoxLostFocus(object sender, RoutedEventArgs routedEventArgs)
		{
			WatermarkVisible = true;
		}

		/// <summary>
		/// Removes the watermark.
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="routedEventArgs"></param>
		void HandleTextBoxGotFocus(object sender, RoutedEventArgs routedEventArgs)
		{
			WatermarkVisible = false;
		}

		/// <summary>
		/// Helper method to determine our associated element, or any CHILD of our parent has focus.
		/// </summary>
		/// <returns></returns>
		bool IsTextBoxFocussed()
		{
			var focusedElement = FocusManager.GetFocusedElement() as DependencyObject;
			bool focused = (focusedElement == AssociatedObject)
							|| (focusedElement != null 
									&& focusedElement.GetVisualAncestors<TextBox>(
															v => v == AssociatedObject).Any());

			return focused;
		}

		void HandleTextBoxTextChanged(object sender, TextChangedEventArgs e)
		{
			if (!IsTextBoxFocussed() && !WatermarkVisible)
			{
				if (string.IsNullOrEmpty(AssociatedObject.Text))
				{
					WatermarkVisible = true;
				}
				else
				{
					if (foregroundBrush != null)
					{
						AssociatedObject.Foreground = foregroundBrush;
					}
					else
					{
						AssociatedObject.ClearValue(Control.ForegroundProperty);
					}
				}
			}
		}
	}

}
